WELL; Phys Ed: Pondering Effects of a Long-Ago Knock on the Head

By GRETCHEN REYNOLDS

Published: July 17, 2012

Much has been studied and reported, particularly in this newspaper, about the short-term effects of concussions on young athletes, as well as the potential longer-term outcomes for professional athletes who engage in high-level contact sports like football and ice hockey for many years, putting themselves at risk for multiple concussions and the lesser but still consequential subconcussive injuries.

But until recently, far less has been understood about the long-term implications, if any, of concussions experienced years ago by recreational athletes. Does a 55-year-old man who played high school football in the '70s and perhaps grew dizzy or ''had his bell rung'' after a tackle or two need to worry about the state of his brain today, even if he never had a formal diagnosis of concussion? Or do I, because I bounced my head hard against the slopes several times while learning to snowboard 10 years ago?

The emerging answer, according to recent research, would seem to be a cautious ''probably not,'' although there may be reason to monitor how easily names and places come to mind.

For a study published in May in the journal Cerebral Cortex, researchers at the University of Montreal examined the brains of a group of healthy, middle-aged former athletes, all of whom had played contact sports in college about 30 years ago and some of whom had sustained concussions while doing so.

In the years since, the athletes had stopped competing but had remained physically active. None complained of failing memories or other symptoms of cognitive impairment - or at least, not more so than any group of 50- and 60-year-olds would be expected to complain.

The researchers scanned the volunteers' brains using M.R.I. machines and automated measuring techniques that precisely determine the volume and other structural components of various brain segments. They also used separate scanning technology that looks at the metabolic health of particular neurons. Finally, they had volunteers complete tests of their long- and short-term memory, including their ability to dredge up specific words, a task that many of us who've reached middle age find daunting.

When the Canadian scientists closely parsed the data from the former athletes, they found small dissimilarities between the brains of those who'd been concussed and those who had not. Many of those who'd been hit in the head decades ago now had slightly less volume in the hippocampus, a brain area associated with memory and learning, than those who hadn't been concussed. Many also had slightly thinner cortexes, especially in portions of the brain known to thin with age. Some also showed signs of metabolic slowing and other abnormalities within their brain cells. And many were just a bit less able to recall events and dredge up words and names than the volunteers who'd never been hit in the head.

The differences, subtle as they were, were reminiscent, the authors concluded, of ''abnormal aging.'' In effect, the concussed brains seemed to be biologically older than the uninjured brains. The 50-year-olds who'd been hit in the head had brains that were structurally and metabolically similar to those of uninjured 60-year-olds.

And this premature brain aging is a potential consequence of past concussions that bears watching, says Steven P. Broglio, a professor of kinesiology with the Michigan Neurosport program at the University of Michigan.

Dr. Broglio, who has extensively studied concussions in college students, is an author of a new review, published this month in Exercise and Sport Sciences Reviews, of possible links between sports-related concussions and premature brain aging. In his work, he's seen lingering if slight declines in college students' ability to concentrate and attend to information, as well as in their balance and bodily control several years after a concussion, changes that somewhat mimic those in the bodies and brains of elderly people.

''It seems possible, according to our data and that from other labs,'' that concussions ''may accelerate some of the normal deterioration in cognitive and motor function that we'd expect with aging,'' he says.

But it is also likely that any such effects will vary widely from person to person. ''We know right now that some athletes are more affected by a single concussion than others,'' says Kevin M. Guskiewicz, chairman of exercise and sports science at the University of North Carolina at Chapel Hill, and winner of a MacArthur ''genius grant'' last year for his work studying sports-related concussions. ''And we don't know why.''

Meanwhile, long-term studies, following people who've experienced a concussion ''from their teens into old age,'' have not yet been done, Dr. Broglio says, although he and others are hoping to start such studies soon.

So for now, given the limited state of the available science, what should someone with a history of concussion do? ''I don't think people need to worry too much,'' Dr. Guskiewicz says.

The Canadian former athletes, after all, even those with signs of accelerated aging, were still functioning fine in their daily lives.

''But it's not a bad idea to do some brain training,'' he adds. ''Exercise. Do puzzles. Read. Learn new things. Those are all good for your brain anyway,'' whether you've had a concussion or not.

''I've had three concussions,'' as a high school and collegiate athlete years ago, he continues. ''I work out and do puzzles all the time. It certainly can't hurt.''

This is a more complete version of the story than the one that appeared in print.